Radio-frequency module and communication device

ABSTRACT

A radio-frequency module includes a module substrate; a power amplifier; a first switch connected to an input terminal of the power amplifier; a second switch connected to an output terminal of the power amplifier; and a switch control circuit that controls the first switch and the second switch. The first switch, the second switch, and the switch control circuit are included in a semiconductor IC being integrated into a single chip. The power amplifier and the semiconductor IC are mounted on or above the module substrate. When the module substrate is viewed in a plan view, in the semiconductor IC, the switch control circuit is disposed between the first switch and the second switch.

CROSS-REFERENCE TO RELATED APPLICATION

The present application is based on and claims priority to JapanesePatent Application No. 2020-100393 filed on Jun. 9, 2020 the entirecontents of which being incorporated herein by reference.

BACKGROUND 1. Field of Disclosure

The present disclosure relates to a radio-frequency module and acommunication device.

2. Description of the Related Art

In mobile communication devices, such as mobile phones, in particular,the layout of circuit elements constituting a radio-frequency front-endcircuit becomes complicated as multiband support progresses.

U.S. Patent Application Publication No. 2018/0131501 discloses aconfiguration of a front-end circuit including a power amplifier thatamplifies a transmission signal. On an input side of the poweramplifier, a switch is disposed that switches between input and no inputof a transmission signal from a transceiver circuit to the poweramplifier. This enables a transmission signal output from thetransceiver circuit to be transmitted from an antenna through thefront-end circuit.

However, when the front-end circuit disclosed in U.S. Patent ApplicationPublication No. 2018/0131501 is constructed in a single small-sizedradio-frequency module, a signal path on the input side of the poweramplifier and a signal path on an output side come close to each other,and thus it is likely that isolation between these two signal pathsdeteriorates. When isolation between the above-described two signalpaths deteriorates, an unwanted radio-frequency signal feedback loop isformed between an input and an output of the power amplifier. In thiscase, the power amplifier oscillates under certain conditions, resultingin unstable operation of the power amplifier.

SUMMARY

The present disclosure has been made to solve such issues and aims toprovide a radio-frequency module and a communication device in whichunstable operation of a power amplifier is suppressed and that aresmall-sized.

According to one aspect, the disclosure is directed to a radio frequencymodule including a module substrate; a power amplifier; a first switchconnected to an input terminal of the power amplifier; a second switchconnected to an output terminal of the power amplifier; and a switchcontrol circuit configured to control the first switch and the secondswitch. The first switch, the second switch, and the switch controlcircuit are included in a semiconductor IC being integrated into asingle chip. The power amplifier and the semiconductor IC are mounted onor above the module substrate. When the module substrate is viewed in aplan view, in the semiconductor IC, the switch control circuit isdisposed between the first switch and the second switch.

The present disclosure can provide the radio-frequency module and acommunication device in which unstable operation of the power amplifieris suppressed and that are small-sized.

Other features, elements, characteristics and advantages of the presentdisclosure will become more apparent from the following detaileddescription of preferred embodiments of the present disclosure withreference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a circuit configuration of a radio-frequency moduleand a communication device according to an embodiment;

FIG. 2A is a schematic diagram of a planar configuration of aradio-frequency module according to a practical example;

FIG. 2B is a schematic diagram of a cross-sectional configuration of theradio-frequency module according to the practical example;

FIG. 3A is a schematic diagram of a planar configuration of aradio-frequency module according to a modification; and

FIG. 3B is a schematic diagram of a cross-sectional configuration of theradio-frequency module according to the modification.

DETAILED DESCRIPTION

Embodiments of the present invention will be described in detail below.Note that all of the embodiments described below describe comprehensiveor specific examples. Numerical values, shapes, materials, components,the arrangement and connection configuration of the components, and soforth that are described in the following embodiments are merelyexamples and are not intended to limit the present invention. Ofcomponents in the following practical example and modification, acomponent not described in an independent claim is described as anoptional component. Furthermore, the sizes or size ratio of componentsillustrated in drawings are or is not necessarily exact. In the figures,components that are substantially the same are denoted by the samereference numerals, and a repeated description thereof is omitted orsimplified in some cases.

Furthermore, in the following description, terms, such as “parallel” and“perpendicular”, representing a relationship between elements, a term,such as “rectangular”, representing the shape of an element, and anumerical range refer to not only their exact meaning but also asubstantially equivalent range, for example, the inclusion of adifference of about a few percent.

Furthermore, in the following description, with respect to A, B, and Cmounted on or above a substrate, “when the substrate (or a main surfaceof the substrate) is viewed in a plan view, C is disposed between A andB” refers to the fact that, when the substrate is viewed in a plan view,at least one of a plurality of line segments connecting points within aregion of A with points within a region of B passes through a region ofC. Furthermore, “the substrate is viewed in a plan view” refers to thefact that the substrate and circuit elements mounted on or above thesubstrate that have been orthographically projected onto a planeparallel to the main surface of the substrate are viewed.

Furthermore, in the following description, “transmission path” refers toa transmission line including a line through which a radio-frequencytransmission signal propagates, an electrode directly connected to theline, a terminal directly connected to the line or the electrode, and soforth. Additionally, “reception path” refers to a transmission lineincluding a line through which a radio-frequency reception signalpropagates, an electrode directly connected to the line, a terminaldirectly connected to the line or the electrode, and so forth. Besides,“transmission-reception path” refers to a transmission line including aline through which a radio-frequency transmission signal and aradio-frequency reception signal propagate, an electrode directlyconnected to the line, a terminal directly connected to the line or theelectrode, and so forth.

Embodiment

1. Circuit Configuration of Radio-Frequency Module 1 and CommunicationDevice 5

FIG. 1 illustrates a circuit configuration of a radio-frequency module 1and a communication device 5 according to an embodiment. As illustratedin FIG. 1, the communication device 5 includes the radio-frequencymodule 1, an antenna 2, and a radio-frequency (RF) signal processingcircuit (RFIC) 3.

The RFIC 3 is an RF signal processing circuit that processesradio-frequency signals transmitted and received by the antenna 2.Specifically, the RFIC 3 performs, through down-conversion or the like,signal processing on a reception signal input through a reception pathof the radio-frequency module 1 and outputs a reception signal generatedthrough the signal processing to a baseband signal processing circuit(not illustrated). Furthermore, the RFIC 3 performs, throughup-conversion or the like, signal processing on a transmission signalinput from the baseband signal processing circuit and outputs atransmission signal generated through the signal processing to atransmission path of the radio-frequency module 1.

Furthermore, the RFIC 3 also has a function of a control unit thatcontrols connections of switches 31, 32, 33, and 34 included in theradio-frequency module 1 in accordance with information, such as acommunication band (frequency band) that is used. Specifically, the RFIC3 switches connections of the switches 31 to 34 included in theradio-frequency module 1 in accordance with a control signal.Specifically, the RFIC 3 outputs digital control signals for controllingthe switches 31 to 34 to a control circuit 40 through a control signalterminal 130. A switch control circuit 41 of the control circuit 40outputs, in accordance with digital control signals input from the RFIC3, digital control signals to the switches 31 to 34, and therebycontrols connections and disconnections of the switches 31 to 34.

Furthermore, the RFIC 3 also has a function of the control unit thatcontrols the gain of a power amplifier 10 included in theradio-frequency module 1, and a power-supply voltage Vcc and a biasvoltage Vbias that are supplied to the power amplifier 10. Specifically,the RFIC 3 outputs digital control signals to the control circuit 40through the control signal terminal 130. A PA control circuit 42 of thecontrol circuit 40 outputs, in accordance with digital control signalsinput from the RFIC 3, a control signal and a power-supply voltage Vccor bias voltage Vbias to the power amplifier 10, and thereby adjusts thegain of the power amplifier 10. Incidentally, a control signal terminalthat receives, from the RFIC 3, digital control signals for controllingthe switches 31 to 34, a control signal terminal that receives, from theRFIC 3, digital control signals for controlling the gain of the poweramplifier 10, and a control signal terminal that receives, from the RFIC3, digital control signals for controlling a power-supply voltage Vccand a bias voltage Vbias that are supplied to the power amplifier 10 maydiffer from one another. Furthermore, the control unit may be providedoutside the RFIC 3.

The antenna 2 is connected to an antenna connection terminal 100 of theradio-frequency module 1 and emits a radio-frequency signal output fromthe radio-frequency module 1. Furthermore, the antenna 2 receives aradio-frequency signal from the outside and outputs the radio-frequencysignal to the radio-frequency module 1.

Incidentally, in the communication device 5 according to the presentembodiment, the antenna 2 is not an indispensable component.

Next, a detailed configuration of the radio-frequency module 1 will bedescribed.

As illustrated in FIG. 1, the radio-frequency module 1 includes theantenna connection terminal 100, transmission input terminals 111 and112, a reception output terminal 120, the control signal terminal 130,the power amplifier 10, a low noise amplifier 20, the control circuit40, transmission filters 61T and 62T, reception filters 61R and 62R,matching networks 51 and 52, and the switches 31, 32, 33, and 34.

The antenna connection terminal 100 is connected to the antenna 2.

The power amplifier 10 is a transmission amplifier capable of amplifyingradio-frequency signals in a communication band A and a communicationband B input from the transmission input terminals 111 and 112.Incidentally, the radio-frequency module 1 may include, in place of thepower amplifier 10, a first power amplifier that amplifies aradio-frequency signal in the communication band A and a second poweramplifier that amplifies a radio-frequency signal in the communicationband B.

The control circuit 40 includes the switch control circuit 41 and the PAcontrol circuit 42. The control circuit 40 includes a logic circuit forgenerating control signals that control the switches 31 to 34 and thepower amplifier 10 in accordance with digital control signals inputthrough the control signal terminal 130.

The switch control circuit 41 controls connections and disconnections ofthe switches 31 to 34 in accordance with digital control signals inputthrough the control signal terminal 130.

The PA control circuit 42 is an example of an amplifier control circuit.The PA control circuit 42 adjusts the gain of the power amplifier 10 inaccordance with digital control signals input through the control signalterminal 130. Incidentally, the PA control circuit 42 may include a biassupply circuit that generates a bias signal that is supplied to thepower amplifier 10.

The low noise amplifier 20 is a reception amplifier that is capable ofamplifying radio-frequency signals in the communication bands A and Bwith low noise and that outputs the radio-frequency signals to thereception output terminal 120. Incidentally, the radio-frequency module1 may include a plurality of low noise amplifiers. For example, theradio-frequency module 1 may include a first low noise amplifier thatamplifies a radio-frequency signal in the communication band A and asecond low noise amplifier that amplifies a radio-frequency signal inthe communication band B.

Each of the power amplifier 10 and the low noise amplifier 20 isconstituted, for example, by a field effect transistor (FET) orheterojunction bipolar transistor (HBT) made of a silicon (Si)-basedcomplementary metal oxide semiconductor (CMOS) or gallium arsenide(GaAs) material.

The transmission filter 61T is disposed in a transmission pathconnecting the transmission input terminals 111 and 112 with the antennaconnection terminal 100 and passes, of transmission signals amplified bythe power amplifier 10, a transmission signal in a transmission band ofthe communication band A. Furthermore, the transmission filter 62T isdisposed in a transmission path connecting the transmission inputterminals 111 and 112 with the antenna connection terminal 100 andpasses, of transmission signals amplified by the power amplifier 10, atransmission signal in a transmission band of the communication band B.

The reception filter 61R is disposed in a reception path connecting thereception output terminal 120 and the antenna connection terminal 100and passes, of reception signals input from the antenna connectionterminal 100, a reception signal in a reception band of thecommunication band A. Furthermore, the reception filter 62R is disposedin a reception path connecting the reception output terminal 120 and theantenna connection terminal 100 and passes, of reception signals inputfrom the antenna connection terminal 100, a reception signal in areception band of the communication band B.

The transmission filter 61T and the reception filter 61R constitute aduplexer 61 whose pass band is the communication band A. The duplexer 61transmits a transmission signal and a reception signal in thecommunication band A by using a frequency division duplex (FDD) scheme.Furthermore, the transmission filter 62T and the reception filter 62Rconstitute a duplexer 62 whose pass band is the communication band B.The duplexer 62 transmits a transmission signal and a reception signalin the communication band B by using the FDD scheme.

Incidentally, each of the duplexers 61 and 62 may be a multiplexerincluding only a plurality of transmission filters, a multiplexerincluding only a plurality of reception filters, or a multiplexerincluding a plurality of duplexers. Furthermore, the transmission filter61T and the reception filter 61R do not have to constitute the duplexer61. Alternatively, one filter may be provided that performs transmissionby using a time division duplex (TDD) scheme. In this case, a switch forswitching between transmission and reception is disposed in at least oneof stages preceding and subsequent to the above-described one filter.Furthermore, similarly, the transmission filter 62T and the receptionfilter 62R do not have to constitute the duplexer 62. Alternatively, onefilter may be provided that performs transmission by using the TDDscheme.

Furthermore, each of the transmission filters 61T and 62T and thereception filters 61R and 62R may be, for example, any of an acousticwave filter using a surface acoustic wave (SAW), an acoustic wave filterusing a bulk acoustic wave (BAW), an LC resonant filter, and adielectric filter, and is further not limited to these.

The matching network 51 is an example of an impedance matching network.The matching network 51 is disposed in a transmission path connectingthe power amplifier 10 and the switch 32 and provides impedance matchingbetween the power amplifier 10 and the switch 32 and duplexers 61 and62. The matching network 52 is disposed in a reception path connectingthe low noise amplifier 20 and the switch 34 and provides impedancematching between the low noise amplifier 20 and the switch 34 andduplexers 61 and 62.

The switch 31 is an example of a first switch connected to an inputterminal of the power amplifier 10 and includes a common terminal 31 aand selection terminals 31 b and 31 c. The common terminal 31 a isconnected to the input terminal of the power amplifier 10. The selectionterminal 31 b is connected to the transmission input terminal 111, andthe selection terminal 31 c is connected to the transmission inputterminal 112. In this connection configuration, the switch 31 switchesbetween a connection between the power amplifier 10 and the transmissioninput terminal 111 and a connection between the power amplifier 10 andthe transmission input terminal 112. The switch 31 is constituted, forexample, by a single pole double throw (SPDT) switch circuit.

From the transmission input terminal 111, for example, a transmissionsignal in the communication band A is input. From the transmission inputterminal 112, for example, a transmission signal in the communicationband B is input. Incidentally, from the transmission input terminal 111,for example, a transmission signal in the communication band A or B inthe fourth generation mobile communication system (4G) may be input,and, from the transmission input terminal 112, for example, atransmission signal in the communication band A or B in the fifthgeneration mobile communication system (5G) may be input.

Furthermore, the switch 31 may have a configuration in which the commonterminal 31 a is connected to one transmission input terminal, in whichthe selection terminal 31 b is connected to the first power amplifierthat amplifies a transmission signal in the communication band A, and inwhich the selection terminal 31 c is connected to the second poweramplifier that amplifies a transmission signal in the communication bandB.

Furthermore, the switch 31 may be constituted by a double pole doublethrow (DPDT) switch circuit including two common terminals and twoselection terminals. In this case, the transmission input terminal 111is connected to one common terminal, and the transmission input terminal112 is connected to the other common terminal. Furthermore, oneselection terminal is connected to the first power amplifier thatamplifies a transmission signal in the communication band A, and theother selection terminal is connected to the second power amplifier thatamplifies a transmission signal in the communication band B. In thisconnection configuration, the switch 31 switches between a connectionbetween the one common terminal and the one selection terminal and aconnection between the one common terminal and the other selectionterminal, and also switches between a connection between the othercommon terminal and the one selection terminal and a connection betweenthe other common terminal and the other selection terminal.

In this case, for example, a transmission signal in the communicationband A is input from the transmission input terminal 111, and atransmission signal in the communication band B is input from thetransmission input terminal 112. Furthermore, for example, transmissionsignals in the communication band A and the communication band B in 4Gmay be input from the transmission input terminal 111, and transmissionsignals in the communication band A and the communication band B in 5Gmay be input from the transmission input terminal 112.

The switch 32 is an example of a second switch connected to an outputterminal of the power amplifier 10 through the matching network 51 andincludes a common terminal 32 a and selection terminals 32 b and 32 c.The common terminal 32 a is connected to the output terminal of thepower amplifier 10 through the matching network 51. The selectionterminal 32 b is connected to the transmission filter 61T, and theselection terminal 32 c is connected to the transmission filter 62T. Inthis connection configuration, the switch 32 switches between aconnection and a disconnection between the power amplifier 10 and thetransmission filter 61T and switches between a connection and adisconnection between the power amplifier 10 and the transmission filter62T. The switch 32 is constituted, for example, by an SPDT switchcircuit.

The switch 34 is connected to an input terminal of the low noiseamplifier 20 through the matching network 52 and includes a commonterminal 34 a and selection terminals 34 b and 34 c. The common terminal34 a is connected to the input terminal of the low noise amplifier 20through the matching network 52. The selection terminal 34 b isconnected to the reception filter 61R, and the selection terminal 34 cis connected to the reception filter 62R. In this connectionconfiguration, the switch 34 switches between a connection and adisconnection between the low noise amplifier 20 and the receptionfilter 61R and switches between a connection and a disconnection betweenthe low noise amplifier 20 and the reception filter 62R. The switch 34is constituted, for example, by an SPDT switch circuit.

The switch 33 is an example of an antenna switch that switches between aconnection and a disconnection between the antenna connection terminal100 and the duplexer 61 and also switches between a connection and adisconnection between the antenna connection terminal 100 and theduplexer 62. The switch 33 includes a common terminal 33 a and selectionterminals 33 b and 33 c. The common terminal 33 a is connected to theantenna connection terminal 100, the selection terminal 33 b isconnected to the duplexer 61, and the selection terminal 33 c isconnected to the duplexer 62. The switch 33 is constituted, for example,by an SPDT switch circuit.

Incidentally, the numbers of common terminals and selection terminalsincluded in the switches 31 to 34 are appropriately set in accordancewith the number of signal paths included in the radio-frequency module1.

The switches 31 and 32 and the switch control circuit 41 are included ina first semiconductor integrated circuit (IC) being integrated into asingle chip. The first semiconductor IC is constructed, for example, byCMOS. Specifically, the first semiconductor IC is formed by asilicon-on-insulator (SOI) process. Thus, the first semiconductor IC canbe fabricated inexpensively. Incidentally, the first semiconductor ICmay be made of at least any of GaAs, silicon germanium (SiGe), andgallium nitride (GaN). Thus, in the case where the first semiconductorIC includes an amplifier, a radio-frequency signal having high-qualityamplification performance and noise performance can be output.

Furthermore, the low noise amplifier 20 and the switch 34 may be formedin a second semiconductor IC being integrated into a single chip.Additionally, the first semiconductor IC and the second semiconductor ICmay be included in a third semiconductor IC being integrated into asingle chip.

In the configuration of the radio-frequency module 1, the switch 31, thepower amplifier 10, the matching network 51, the switch 32, thetransmission filter 61T, and the switch 33 constitute a firsttransmission circuit that transmits a transmission signal in thecommunication band A toward the antenna connection terminal 100.Furthermore, the switch 33, the reception filter 61R, the switch 34, thematching network 52, and the low noise amplifier 20 constitute a firstreception circuit that transmits a reception signal in the communicationband A from the antenna 2 through the antenna connection terminal 100.Additionally, the switch 31, the power amplifier 10, the matchingnetwork 51, the switch 32, the transmission filter 62T, and the switch33 constitute a second transmission circuit that transmits atransmission signal in the communication band B toward the antennaconnection terminal 100. Besides, the switch 33, the reception filter62R, the switch 34, the matching network 52, and the low noise amplifier20 constitute a second reception circuit that transmits a receptionsignal in the communication band B from the antenna 2 through theantenna connection terminal 100.

In the above-described circuit configuration, the radio-frequency module1 can perform at least any of transmission, reception, and transmissionand reception of a radio-frequency signal or signals in thecommunication band A or communication band B. Furthermore, theradio-frequency module 1 can also perform at least any of simultaneoustransmission, simultaneous reception, and simultaneous transmission andreception of radio-frequency signals in the communication band A and thecommunication band B.

Incidentally, in a radio-frequency module according to the presentinvention, the above-described two transmission circuits and theabove-described two reception circuits do not have to be connected tothe antenna connection terminal 100 through the switch 33. Theabove-described two transmission circuits and the above-described tworeception circuits may be connected to the antenna 2 through a differentterminal.

Incidentally, a radio-frequency module according to the presentinvention only has to include, of circuit components of theradio-frequency module 1 illustrated in FIG. 1, at least the poweramplifier 10, at least the switches 31 and 32, and at least the switchcontrol circuit 41.

Here, in the case where the radio-frequency module 1 is miniaturized, asignal path on an input side of the power amplifier 10 and a signal pathon an output side come close to each other, and thus it is likely thatisolation between these two signal paths deteriorates. When isolationbetween the above-described two signal paths deteriorates, an unwantedradio-frequency signal feedback loop is formed between an input and anoutput of the power amplifier 10. In this case, the power amplifier 10oscillates under certain conditions, resulting in unstable operationthereof. On the other hand, a configuration of the radio-frequencymodule 1 in which oscillation of the power amplifier 10 is reduced andthat is small-sized will be described below.

2. Layout of Circuit Elements in Radio-Frequency Module 1A According toPractical Example

FIG. 2A is a schematic diagram of a planar configuration of aradio-frequency module 1A according to a practical example. Furthermore,FIG. 2B is a schematic diagram of a cross-sectional configuration of theradio-frequency module 1A according to the practical example,specifically, a cross-sectional diagram taken along line IIB-IIB in FIG.2A. Incidentally, (a) of FIG. 2A illustrates a layout diagram of circuitelements when, of main surfaces 91 a and 91 b on opposite sides of amodule substrate 91, the main surface 91 a is viewed from a positiveside of a z axis. On the other hand, (b) of FIG. 2A illustrates thelayout of circuit elements as seen through the main surface 91 b whenthe main surface 91 b is viewed from the positive side of the z axis.

The diagram of the radio-frequency module 1A according to the practicalexample specifically illustrates the layout of circuit elementsconstituting the radio-frequency module 1 according to the embodiment.

As illustrated in FIGS. 2A and 2B, the radio-frequency module 1Aaccording to the present practical example further includes the modulesubstrate 91, resin members 92 and 93, and external connection terminals150 in addition to the circuit configuration illustrated in FIG. 1.

The module substrate 91 has the main surface 91 a (first main surface)and the main surface 91 b (second main surface) opposite to each otherand is a substrate where the above-described transmission circuits andthe above-described reception circuits are mounted. As the modulesubstrate 91, for example, a low temperature co-fired ceramic (LTCC)substrate having a stacked structure including a plurality of dielectriclayers, a high temperature co-fired ceramic (HTCC) substrate, asubstrate with a built-in component, a substrate with a redistributionlayer (RDL), or a printed circuit substrate is used.

The resin member 92 is disposed on the main surface 91 a of the modulesubstrate 91 and covers part of the above-described transmissioncircuits, part of the above-described reception circuits, and the mainsurface 91 a of the module substrate 91. The resin member 92 has afunction of ensuring the reliability of, for example, the mechanicalstrength and moisture resistance of circuit elements constituting theabove-described transmission circuits and the above-described receptioncircuits. The resin member 93 is disposed on the main surface 91 b ofthe module substrate 91 and covers part of the above-describedtransmission circuits, part of the above-described reception circuits,and the main surface 91 b of the module substrate 91. The resin member93 has a function of ensuring the reliability of, for example, themechanical strength and moisture resistance of circuit elementsconstituting the above-described transmission circuits and theabove-described reception circuits. Incidentally, the resin members 92and 93 are not indispensable components to a radio-frequency moduleaccording to the present invention.

As illustrated in FIGS. 2A and 2B, in the radio-frequency module 1Aaccording to the present practical example, the power amplifier 10, theduplexers 61 and 62, and the matching networks 51 and 52 are disposed onor above the main surface 91 a (first main surface). On the other hand,the control circuit 40, the switches 31 to 34, and the low noiseamplifier 20 are disposed on or above the main surface 91 b (second mainsurface).

Incidentally, although not illustrated in FIG. 2A, lines constituting atransmission path and a reception path that connect circuit componentsillustrated in FIG. 1 are formed within the module substrate 91 and onthe main surfaces 91 a and 91 b. Furthermore, each of theabove-described lines may be a bonding wire with each end bonded to anyof the main surfaces 91 a and 91 b and a circuit element constitutingthe radio-frequency module 1A, or alternatively may be a terminal,electrode, or line formed on a surface of a circuit element constitutingthe radio-frequency module 1A.

Here, as illustrated in (b) of FIG. 2A, the switches 31 and 32 and thecontrol circuit 40 are included in a semiconductor IC 70 beingintegrated into a single chip (also referred to as a die). Incidentally,a situation in which a plurality of circuit elements are included in asemiconductor IC being integrated into a single chip is defined as asituation in which the plurality of circuit elements are formed on asurface of or within one semiconductor substrate, or a situation inwhich the plurality of circuit elements are integrally disposed in asingle package. Furthermore, the above-described one semiconductorsubstrate and the above-described single package differ from the modulesubstrate 91 and further differ from an external substrate where theradio-frequency module 1A is mounted.

Furthermore, as illustrated in (b) of FIG. 2A, when the module substrate91 is viewed in a plan view, in the semiconductor IC 70, the controlcircuit 40 is disposed between the switch 31 and the switch 32.

In the above-described configuration, the switches 31 and 32 and thecontrol circuit 40 are formed in the semiconductor IC 70 beingintegrated into the single chip, thus making it possible to promoteminiaturization of the radio-frequency module 1A. Furthermore, theswitch 31 disposed in the signal path on the input side of the poweramplifier 10 and the switch 32 disposed in the signal path on the outputside are separated by the control circuit 40, and thus electromagneticfield coupling between the switch 31 and the switch 32 can be reduced.Furthermore, the length of a control line connecting the switch 31 andthe switch control circuit 41 and the length of a control lineconnecting the switch 32 and the switch control circuit 41 can bereduced, and thus electromagnetic field coupling between these twocontrol lines can be reduced. Hence, deterioration of isolation betweenthe signal path on the input side of the power amplifier 10 and thesignal path on the output side is inhibited, and thus the poweramplifier 10 can be kept from oscillating due to formation of anunwanted radio-frequency signal feedback loop between the input and theoutput of the power amplifier 10. Furthermore, not only the switchcontrol circuit 41 but also the PA control circuit 42 is built in thesemiconductor IC 70, and thus a distance between the switch 31 and theswitch 32 can be increased further.

Furthermore, the radio-frequency module 1A exchanges electrical signalswith the external substrate disposed on a negative z-axis side of theradio-frequency module 1A through the external connection terminals 150.As illustrated in (b) of FIG. 2A, included among the external connectionterminals 150 are the antenna connection terminal 100, the transmissioninput terminals 111 and 112, the reception output terminal 120, and thecontrol signal terminal 130. Furthermore, some of the externalconnection terminals 150 are set at a ground potential of the externalsubstrate.

Of the main surfaces 91 a and 91 b, on or above the main surface 91 bopposite to the external substrate, the power amplifier 10 that isdifficult to reduce in height is not disposed, but the control circuit40, the low noise amplifier 20, and the switches 31 to 34 that are easyto reduce in height are disposed, thus enabling a reduction in theheight of the entire radio-frequency module 1A. Furthermore, around thelow noise amplifier 20 that greatly affects reception sensitivity of thereception circuits, a plurality of external connection terminals 150used as ground electrodes are disposed, thus making it possible toinhibit deterioration of reception sensitivity of the receptioncircuits.

Furthermore, in the radio-frequency module 1A, the power amplifier 10 isdisposed on or above the main surface 91 a. The power amplifier 10 is acomponent that generates the largest amount of heat of circuitcomponents included in the radio-frequency module 1A. To improve heatdissipation of the radio-frequency module 1A, it is desirable todissipate heat generated by the power amplifier 10 to the externalsubstrate by using a heat dissipation path with a small thermalresistance. If the power amplifier 10 is mounted on or above the mainsurface 91 b, an electrode line connected to the power amplifier 10 isdisposed on the main surface 91 b. For this reason, as a heatdissipation path, a heat dissipation path extending only through aplanar wiring pattern (along an x-y planar direction) on the mainsurface 91 b is included. The above-described planar wiring pattern isformed from a thin metal film and thus has a large thermal resistance.As a result, when the power amplifier 10 is disposed on the main surface91 b, heat dissipation is reduced.

On the other hand, when the power amplifier 10 is disposed on or abovethe main surface 91 a, the power amplifier 10 and the external substratecan be connected to each other through a ground via conductor extendingbetween the main surface 91 a and the main surface 91 b. Thus, as a heatdissipation path of the power amplifier 10, a heat dissipation pathextending only through the planar wiring pattern that has a largethermal resistance and extends along the x-y planar direction can beexcluded. Hence, the radio-frequency module 1A in which heat dissipationfrom the power amplifier 10 to the external substrate is improved andthat is small-sized can be provided.

Furthermore, in the radio-frequency module 1A according to the presentpractical example, the low noise amplifier 20 is disposed on or abovethe main surface 91 b.

Thus, the power amplifier 10 that amplifies a transmission signal andthe low noise amplifier 20 that amplifies a reception signal aredisposed separately on or above both the respective surfaces of themodule substrate 91, therefore improving isolation between transmissionand reception.

Incidentally, the module substrate 91 has a multilayer structure inwhich a plurality of dielectric layers are stacked on top of oneanother, and it is desirable that a ground electrode pattern is formedin at least one of the plurality of dielectric layers. This improves anelectromagnetic field shielding function of the module substrate 91.

Furthermore, in the radio-frequency module 1A according to the presentpractical example, the matching network 51 is disposed on or above themain surface 91 a. The matching network 51 includes an inductor.

Thus, the switch 31 disposed in the signal path on the input side of thepower amplifier 10 and the matching network 51 disposed in the signalpath on the output side are disposed separately on or above therespective main surfaces 91 b and 91 a of the module substrate 91, andelectromagnetic field coupling between the switch 31 and the matchingnetwork 51 can therefore be reduced. Hence, deterioration of isolationbetween the signal path on the input side of the power amplifier 10 andthe signal path on the output side is inhibited further.

Furthermore, the low noise amplifier 20 and the switches 33 and 34 areincluded in a single semiconductor IC 80. Thus, the semiconductor ICs 70and 80 that are easy to reduce in height are disposed on the mainsurface 91 b, therefore enabling a reduction in the height of the entireradio-frequency module 1A.

Incidentally, the semiconductor IC 70 and the semiconductor IC 80 may beintegrated into a single semiconductor IC. Furthermore, thesemiconductor IC 70 may include at least one of the low noise amplifier20 and the switches 33 and 34.

Incidentally, in the radio-frequency module 1A according to the presentpractical example, the power amplifier 10, the duplexers 61 and 62, andthe matching networks 51 and 52 are disposed on or above the mainsurface 91 a, and the control circuit 40, the switches 31 to 34, and thelow noise amplifier 20 are disposed on or above the main surface 91 b.However, in a radio-frequency module according to the present invention,the above-described circuit elements may be disposed on or above anymain surface, or alternatively may be formed within the module substrate91.

Incidentally, in the radio-frequency module 1A, the external connectionterminals 150 may be columnar electrodes extending through the resinmember 93 in a z-axis direction as illustrated in FIG. 2B.Alternatively, as in a radio-frequency module 1B according to amodification to be described, external connection terminals may be bumpelectrodes formed on the main surface 91 b. In this case, the resinmember 93 on a main surface 91 b side does not have to be provided.

3. Layout of Circuit Elements in Radio-Frequency Module 1B According toModification

FIG. 3A is a schematic diagram of a planar configuration of theradio-frequency module 1B according to a modification. Furthermore, FIG.3B is a schematic diagram of a cross-sectional configuration of theradio-frequency module 1B according to the modification, specifically, across-sectional diagram taken along line IIIB-IIIB in FIG. 3A.Incidentally, (a) of FIG. 3A illustrates a layout diagram of circuitelements when, of the main surfaces 91 a and 91 b opposite to each otherof the module substrate 91, the main surface 91 a is viewed from apositive side of a z axis. On the other hand, (b) of FIG. 3A illustratesthe layout of circuit elements as seen through the main surface 91 bwhen the main surface 91 b is viewed from the positive side of the zaxis.

The diagram of the radio-frequency module 1B according to themodification specifically illustrates the layout of circuit elementsconstituting the radio-frequency module 1 according to the embodiment.

The radio-frequency module 1B according to the present modificationdiffers from the radio-frequency module 1A according to the practicalexample in the placement of the PA control circuit 42. With respect tothe radio-frequency module 1B according to the present modification, adescription of things in common with the radio-frequency module 1Aaccording to the practical example is omitted, and a description will begiven below with emphasis on respects in which the radio-frequencymodule 1B differs from the radio-frequency module 1A.

As illustrated in FIGS. 3A and 3B, the radio-frequency module 1Baccording to the present modification further includes the modulesubstrate 91, the resin member 92, and bump electrodes 160 in additionto the circuit configuration illustrated in FIG. 1.

As illustrated in FIGS. 3A and 3B, in the radio-frequency module 1Baccording to the present modification, the power amplifier 10, the PAcontrol circuit 42, the duplexers 61 and 62, and the matching networks51 and 52 are disposed on or above the main surface 91 a (first mainsurface). On the other hand, the switch control circuit 41, the switches31 to 34, and the low noise amplifier 20 are disposed on or above themain surface 91 b (second main surface).

Here, as illustrated in (b) of FIG. 3A, the switches 31 and 32 and theswitch control circuit 41 are included in a semiconductor IC 71 beingintegrated into a single chip.

Furthermore, as illustrated in (b) of FIG. 3A, when the module substrate91 is viewed in a plan view, in the semiconductor IC 71, the switchcontrol circuit 41 is disposed between the switch 31 and the switch 32.

In the above-described configuration, the switches 31 and 32 and theswitch control circuit 41 are formed in the semiconductor IC 71 beingintegrated into the single chip, thus making it possible to promoteminiaturization of the radio-frequency module 1B. Furthermore, theswitch 31 disposed in the signal path on the input side of the poweramplifier 10 and the switch 32 disposed in the signal path on the outputside are separated by the switch control circuit 41, and thuselectromagnetic field coupling between the switch 31 and the switch 32can be reduced. Furthermore, the length of the control line connectingthe switch 31 and the switch control circuit 41 and the length of thecontrol line connecting the switch 32 and the switch control circuit 41can be reduced, and thus electromagnetic field coupling between thesetwo control lines can be reduced. Hence, deterioration of isolationbetween the signal path on the input side of the power amplifier 10 andthe signal path on the output side is inhibited, and thus the poweramplifier 10 can be kept from oscillating due to formation of anunwanted radio-frequency signal feedback loop between the input and theoutput of the power amplifier 10.

Furthermore, in the radio-frequency module 1B, the PA control circuit 42and the power amplifier 10 are stacked on or above the main surface 91a.

Thus, the PA control circuit 42 and the power amplifier 10 are disposedin a stacked manner, therefore making it possible to promoteminiaturization of the radio-frequency module 1B. Furthermore, atemperature differential between the power amplifier 10 and the PAcontrol circuit 42 can be reduced. For this reason, the power amplifier10 and the PA control circuit 42 are disposed in the same temperatureenvironment, and thus accuracy of response of the power amplifier 10that is controlled by the PA control circuit 42 to operate can beincreased. Thus, amplification characteristics of the power amplifier 10can be controlled with high accuracy by the PA control circuit 42, andthe amplification characteristics can therefore be optimized. Hence,deterioration of output characteristics of the power amplifier 10 can beinhibited.

Furthermore, the radio-frequency module 1B exchanges electrical signalswith the external substrate disposed on a negative z-axis side of theradio-frequency module 1B through the bump electrodes 160. The bumpelectrodes 160 are an example of an external connection terminal. Asillustrated in (b) of FIG. 3A, included among the bump electrodes 160are the antenna connection terminal 100, the transmission inputterminals 111 and 112, the reception output terminal 120, and thecontrol signal terminal 130. Furthermore, some of the bump electrodes160 are set at a ground potential of the external substrate.

Of the main surfaces 91 a and 91 b, on or above the main surface 91 bopposite to the external substrate, the power amplifier 10 that isdifficult to reduce in height is not disposed, but the switch controlcircuit 41, the low noise amplifier 20, and the switches 31 to 34 thatare easy to reduce in height are disposed, thus enabling a reduction inthe height of the entire radio-frequency module 1B.

Incidentally, the semiconductor IC 71 and the semiconductor IC 80 may beintegrated into a single semiconductor IC. Furthermore, thesemiconductor IC 71 may include at least one of the low noise amplifier20 and the switches 33 and 34.

Incidentally, in the radio-frequency module 1B according to the presentmodification, the power amplifier 10, the PA control circuit 42, theduplexers 61 and 62, and the matching networks 51 and 52 are disposed onor above the main surface 91 a, and the switch control circuit 41, theswitches 31 to 34, and the low noise amplifier 20 are disposed on orabove the main surface 91 b. However, in a radio-frequency moduleaccording to the present invention, the above-described circuit elementsmay be disposed on or above any main surface, or alternatively may beformed within the module substrate 91.

Incidentally, in the radio-frequency module 1B, the bump electrodes 160may be columnar electrodes extending through the resin member 93 in az-axis direction as in the radio-frequency module 1A according to thepractical example.

4. Effects

As described above, the radio-frequency module 1 according to thepresent embodiment includes the module substrate 91; the power amplifier10; the switch 31 connected to the input terminal of the power amplifier10; the switch 32 connected to the output terminal of the poweramplifier 10; and the switch control circuit 41 that controls theswitches 31 and 32. The switches 31 and 32 and the switch controlcircuit 41 are included in the semiconductor IC 70 being integrated intoa single chip. The power amplifier 10 and the semiconductor IC 70 aremounted on or above the module substrate 91. When the module substrate91 is viewed in a plan view, in the semiconductor IC 70, the switchcontrol circuit 41 is disposed between the switch 31 and the switch 32.

In the above-described configuration, the switches 31 and 32 and thecontrol circuit 40 are formed in the semiconductor IC 70 beingintegrated into the single chip, thus making it possible to promoteminiaturization of the radio-frequency module 1. Furthermore, the switch31 and the switch 32 are separated by the switch control circuit 41, andthus electromagnetic field coupling between the switch 31 and the switch32 can be reduced. Furthermore, the length of the control lineconnecting the switch 31 and the switch control circuit 41 and thelength of the control line connecting the switch 32 and the switchcontrol circuit 41 can be reduced, and thus electromagnetic fieldcoupling between these two control lines can be reduced. Hence,deterioration of isolation between the signal path on the input side ofthe power amplifier 10 and the signal path on the output side isinhibited, and thus the power amplifier 10 can be kept from oscillatingdue to formation of an unwanted radio-frequency signal feedback loopbetween the input and the output of the power amplifier 10.

Furthermore, in the radio-frequency module 1, the module substrate 91may have the main surfaces 91 a and 91 b opposite to each other. Theradio-frequency module 1 may further include an external connectionterminal 150 disposed on the main surface 91 b. The semiconductor IC 70may be disposed on the main surface 91 b.

Thus, the switch control circuit 41 and the switches 31 and 32 that areeasy to reduce in height are disposed on or above the main surface 91 b,therefore enabling a reduction in the height of the entireradio-frequency module 1.

Furthermore, in the radio-frequency module 1, the power amplifier 10 maybe disposed on or above the main surface 91 a.

Thus, the power amplifier 10 and the external substrate can be connectedto each other through a ground via conductor extending between the mainsurface 91 a and the main surface 91 b, and, as a heat dissipation pathof the power amplifier 10, a heat dissipation path extending onlythrough a planar wiring pattern that has a large thermal resistance andextends along an x-y planar direction can be excluded. Hence, theradio-frequency module 1 in which heat dissipation from the poweramplifier 10 to the external substrate is improved and that issmall-sized can be provided.

Furthermore, the radio-frequency module 1 may further include the lownoise amplifier 20, and the low noise amplifier 20 may be disposed on orabove the main surface 91 b.

Thus, the power amplifier 10 that amplifies a transmission signal andthe low noise amplifier 20 that amplifies a reception signal aredisposed separately on or above both the respective surfaces of themodule substrate 91, therefore improving isolation between transmissionand reception.

Furthermore, the radio-frequency module 1A may further include the PAcontrol circuit 42 that controls the power amplifier 10, and the PAcontrol circuit 42 may be included in the semiconductor IC 70. When themodule substrate 91 is viewed in a plan view, in the semiconductor IC70, the switch control circuit 41 and the PA control circuit 42 may bedisposed between the switch 31 and the switch 32.

Thus, not only the switch control circuit 41 but also the PA controlcircuit 42 is built in the semiconductor IC 70, and a distance betweenthe switch 31 and the switch 32 can therefore be increased further.

Furthermore, the radio-frequency module 1B may further include the PAcontrol circuit 42 that controls the power amplifier 10, and the poweramplifier 10 and the PA control circuit 42 may be stacked on or abovethe main surface 91 a.

Thus, the PA control circuit 42 and the power amplifier 10 are disposedin a stacked manner, therefore making it possible to promoteminiaturization of the radio-frequency module 1B. Furthermore, atemperature differential between the power amplifier 10 and the PAcontrol circuit 42 can be reduced. Thus, amplification characteristicsof the power amplifier 10 can be controlled with high accuracy by the PAcontrol circuit 42, and the amplification characteristics can thereforebe optimized. Hence, deterioration of output characteristics of thepower amplifier 10 can be inhibited.

Furthermore, the radio-frequency module 1 may further include thematching network 51 connected between the output terminal of the poweramplifier 10 and the switch 32. The matching network 51 may include aninductor, and the inductor may be disposed on or above the main surface91 a.

Thus, the switch 31 and the matching network 51 are disposed separatelyon or above the respective main surfaces 91 b and 91 a of the modulesubstrate 91, and electromagnetic field coupling between the switch 31and the matching network 51 can therefore be reduced. Hence,deterioration of isolation between the signal path on the input side ofthe power amplifier 10 and the signal path on the output side isinhibited further.

Furthermore, the communication device 5 includes the antenna 2; the RFIC3 that processes radio-frequency signals transmitted and received by theantenna 2; and the radio-frequency module 1 that transmits theradio-frequency signals between the antenna 2 and the RFIC 3.

Thus, the communication device 5 in which unstable operation of thepower amplifier 10 is suppressed and that is small-sized can beprovided.

Other Embodiments

Although a radio-frequency module and a communication device accordingto an embodiment of the present invention have been described above bytaking an embodiment, a practical example, and a modification, aradio-frequency module and a communication device according to thepresent invention are not limited to the above-described embodiment,practical example, and modification. The present invention also coversanother embodiment achieved by combining any components in theabove-described embodiment, practical example, and modification,modifications obtained by making various modifications conceived by aperson skilled in the art to the above-described embodiment, practicalexample, and modification within the scope of the gist of the presentinvention, and various devices including the above-describedradio-frequency modules and communication device.

For example, in the radio-frequency modules and the communication deviceaccording to the above-described embodiment, practical example, andmodification, between paths connecting circuit elements and signal pathsthat are illustrated in the drawings, another circuit element, a line,and so forth may be inserted.

The present invention can be widely used, as a radio-frequency moduledisposed in a multiband front-end section, in communication equipment,such as mobile phones.

While preferred embodiments of the invention have been described above,it is to be understood that variations and modifications will beapparent to those skilled in the art without departing from the scopeand spirit of the invention. The scope of the invention, therefore, isto be determined solely by the following claims.

What is claimed is:
 1. A radio-frequency module comprising: a modulesubstrate; a power amplifier; a first switch connected to an inputterminal of the power amplifier; a second switch connected to an outputterminal of the power amplifier; and a switch control circuit configuredto control the first switch and the second switch, wherein the firstswitch, the second switch, and the switch control circuit are includedin a semiconductor integrated circuit (IC) being integrated into asingle chip, the power amplifier and the semiconductor IC are mounted onor above the module substrate, and when the module substrate is viewedin a plan view, in the semiconductor IC, the switch control circuit isphysically positioned between the first switch and the second switch ina manner that a virtual line extending from one side of the modulesubstrate to another side of the module substrate, as viewed in the planview, passes through the control circuit, the first switch and thesecond switch.
 2. The radio-frequency module of claim 1, wherein themodule substrate has a first main surface and a second main surface onopposite sides of the module substrate.
 3. The radio-frequency module ofclaim 2, further comprising: an external connection terminal disposed onthe second main surface.
 4. The radio-frequency module of claim 3,wherein the semiconductor IC is disposed on the second main surface. 5.The radio-frequency module of claim 4, wherein the power amplifier isdisposed on or above the first main surface.
 6. The radio-frequencymodule of claim 5, further comprising: a low noise amplifier disposed onor above the second main surface.
 7. The radio-frequency module of claim1, further comprising: an amplifier control circuit configured tocontrol the power amplifier.
 8. The radio-frequency module of claim 7,wherein the amplifier control circuit is included in the semiconductorIC.
 9. The radio-frequency module of claim 8, wherein when the modulesubstrate is viewed in the plan view, in the semiconductor IC, theswitch control circuit and the amplifier control circuit are disposedbetween the first switch and the second switch.
 10. The radio-frequencymodule of claim 2, further comprising: an amplifier control circuitconfigured to control the power amplifier, wherein the power amplifierand the amplifier control circuit are stacked on or above the first mainsurface.
 11. The radio-frequency module of claim 2, further comprising:an impedance matching network connected between the output terminal ofthe power amplifier and the second switch.
 12. The radio-frequencymodule of claim 11, wherein the impedance matching network includes aninductor disposed on or above the first main surface.
 13. Acommunication device comprising: an antenna; a radio-frequency (RF)signal processing circuit configured to process RF signals transmittedand received by the antenna; and a RF module configured to transmit theRF signals between the antenna and the RF signal processing circuit,wherein the RF module includes a module substrate; a power amplifier; afirst switch connected to an input terminal of the power amplifier; asecond switch connected to an output terminal of the power amplifier;and a switch control circuit configured to control the first switch andthe second switch, the first switch, the second switch, and the switchcontrol circuit are included in a semiconductor integrated circuit (IC)being integrated into a single chip, the power amplifier and thesemiconductor IC are mounted on or above the module substrate, and whenthe module substrate is viewed in a plan view, in the semiconductor IC,the switch control circuit is physically positioned between the firstswitch and the second switch in a manner that a virtual line extendingfrom one side of the module substrate to another side of the modulesubstrate, as viewed in the plan view, passes through the controlcircuit, the first switch and the second switch.
 14. A radio-frequencymodule comprising: a module substrate having a first main surface and asecond main surface on opposite sides of the module substrate; a poweramplifier disposed on the first main surface; a first switch connectedto an input terminal of the power amplifier; a second switch connectedto an output terminal of the power amplifier; and a switch controlcircuit configured to control the first switch and the second switch,wherein the first switch, the second switch, and the switch controlcircuit are included in a semiconductor integrated circuit (IC) disposedon the second main surface.
 15. The radio-frequency module of claim 14,wherein when the module substrate is viewed in a plan view, the switchcontrol circuit is disposed between the first switch and the secondswitch.
 16. The radio-frequency module of claim 14, further comprising:an external connection terminal disposed on the second main surface. 17.The radio frequency module of claim 14, further comprising: a low noiseamplifier disposed on or above the second main surface.
 18. The radiofrequency module of claim 14, further comprising: an amplifier controlcircuit configured to control the power amplifier, wherein the amplifiercontrol circuit is included in the semiconductor IC, and when the modulesubstrate is viewed in the plan view, the switch control circuit and theamplifier control circuit are disposed between the first switch and thesecond switch.
 19. The radio-frequency module of claim 14, furthercomprising: an amplifier control circuit configured to control the poweramplifier, wherein the power amplifier and the amplifier control circuitare stacked on or above the first main surface.
 20. The radio-frequencymodule of claim 14, further comprising: an impedance matching networkconnected between the output terminal of the power amplifier and thesecond switch, wherein the impedance matching network includes aninductor disposed on or above the first main surface.